输入的字符串，把每个单词全部转化成小写字母，对每个单词，看它的字母重排后得到的单词在所有输入的单词中是否出现过，若没有出现，就输出原单词。所有要输出的单词按字典序排列输出。
思路：构造小写化函数，set可以解决去重和排序问题，用map建立string与int的映射
void string stand_words(string s1);
注意要存储原单词！
Resizes the string content to characters.
the content is expanded by appending as many instances of the characters as
needed to reach a size of characters.resizes
a
appending
by
expanded
instances
is
many
needed
reach
size
string